The present invention relates to power drive means in general, and more particularly to a power drive unit for transmitting motive power from the output of a prime mover such as, an internal combustion engine, an electric motor, and the like, to a mechanism utilizing such power for an individual transportation means, such as a bicycle, tricycle or quadricycle, or for driving a machine or tool requiring a source of power.
An example of practical use of the invention is as a power drive unit for bicycles, tricycles or quadricycles. Many attempts have been made in the past to provide bicycles and tricycles with a small auxiliary internal combustion engine as disclosed, for example, in British Pat. spec. No. 1,493, French Pat. No. 535,184, U.S. Pat. Nos. 686,284, 729,197, 1,097,546, 1,094,558, 2,468,367, 2,560,991, 2,633,030, or even with a liquified gas engine, as disclosed in U.S. Pat. No. 673,336 or an impact motor as disclosed in U.S. Pat. No. 686,653. Such arrangements generally require substantial modifications of the basic structure of the two-wheeled or three-wheeled vehicle, to the extent that the vehicle cannot efficiently be returned to, and used in, its original non-motorized form. Motorized bicycles and tricycles, through evolution, have led to a complete transformation of the two-wheeled and three-wheeled vehicles, as represented in modern time by the fully motorized motorcycles and "trikes". Motorcycles, in turn, have evolved back into an hybrid type of vehicle, primarily motorized but with mechanical pedal assist in the event of power failure or in occasions when the non-human power available is insufficient as, for example, during hill climbing or when riding with a strong headwind.
The only attempt known to applicant for providing a conventional bicycle or tricycle, normally pedal-driven, with auxiliary power assist consists in mounting a small internal combustion engine, or an electric motor, above a wheel, generally above the front wheel, driving the wheel through a roller mounted on the engine output shaft and controllably engageable with the wheel tire. Such an arrangement presents many inconveniences as it relies entirely on friction for transmitting power from the engine output to the tire, and causes considerable wear of the tire tread.
The present invention remedies the inconveniences and shortcomings of the prior art by providing an auxiliary power drive for conventional pedal driven bicycles, tricycles and quadricycles, requiring no modification whatsoever to the vehicle frame and conventional pedal powertrain, which is of relatively light weight, which can utilize an internal combustion engine readily available on the market for other uses and which may be returned to its original use without complication, which can be installed on a conventional bicycle, tricycle or quadricycle easily in a few minutes, and which does not interfere with the normal operation of the vehicle by pedal power.
In addition, the power train unit of the present invention has many other applications for utilizing readily available power units for uses other than the uses for which the power units have originally been designed. By utilizing the adapter plate and the power train unit of the invention as a controllably engageable and disengageable power transmitting unit between the output shaft of, for example, a conventional chain saw engine, the chain saw engine may be conveniently used to drive any device requiring a power drive, such as, for example, a personal transportation vehicle, a boat propeller, a light aircraft propeller, an electrical generator, a small concrete mixer, a machine tool, etc.